The Advertising Standards Authority said it feared the direct mail scare campaign could cause "fear and distress" to children.
Six complainants were concerned the envelope might be seen by children who did not understand the full message of the mailing and that it could cause undue "fear and distress" by suggesting that having brown eyes could be a cause of early death.
Designed by Proximity, the mailer also contained text that said "most children born with brown eyes are born in the world's poorest areas" and detailed the plight of children in various countries in Africa and Asia. It asked for a donation of £3 a month.
Save the Children Fund maintained that the mailing was intended to educate recipients about the numbers of children dying in poor countries each year. It apologised for any offence caused and said it would amend the presentation of the mailer if it decided to use it again.
The ASA said "We were concerned that it could cause undue fear and distress to young children who saw it.
"We welcomed the Save the Children's offer to amend the mailing if they decided to use it again and advised them to consult the CAP copy advice team about the presentation of the envelope."
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This article was first published on brandrepublic.com